I dont know if it is my typical luck or if there is an issue but so far Ive had two defective memory modules (2x4G) from crucial. They are a wonderful company so Im not blaming them. On the first set of ram: 2011 MBP 13 i7, posted, ran for a bit then locked up. After that, it would not post (no beeps either). 2011 MBP 17 2.3 posted, ran and locked up when loading iTunes,LR3 or anything else that appeared to use a bit of memory. Reboot and the same thing happens then a panic from then on Second set of ram: 2011 MBP 17 2.3 posted gave 3 beeps- both sticks. One stick verified stable other no post. Running at 6GB and stable late 2009 MBP 17 2.8 (thought this might be a good test for the suspect stick). Posted and booted into Bootcamp win 64. Locked when running the Windows Experience test. After that, post gave 3 beeps. Basically Im just curious if Im the only fool that this type of stuff typically happens too Or are these SB machine more particular than the older.